/**
 * Copyright (c) 2009, Christian Schneider
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 * - Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *  - Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *  - Neither the names of the authors nor the names of its contributors may
 *    be used to endorse or promote products derived from this software without
 *    specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
package name.cs.csutils;

import java.awt.EventQueue;

import javax.swing.SwingUtilities;

public class SynchronizedField<E> implements Runnable {

    private E value;
    private boolean updatingEnabled = true;
    private boolean pendingUpdate = false;
    
    public SynchronizedField(E value) {
        this.value = value;
    }
    
    public synchronized void set(E value) {
        E oldValue = this.value;
        if (oldValue != value) {
            this.value = value;
            if (updatingEnabled) {
                triggerUpdate();
            }
        }
    }
    
    public synchronized E get() {
        return value;
    }
    
    public synchronized void triggerUpdate() {
        pendingUpdate = true;
        if (EventQueue.isDispatchThread()) {
            run();
        } else {
            SwingUtilities.invokeLater(this);
        }
    }
    
    protected void update(E value) {
        // for custom classes
    }
    
    public void run() {
        
        synchronized (this) {
            if (!pendingUpdate) {
                return;
            }
        }
        
        try {
            update(get());
        } finally { 
            synchronized (this) {
                pendingUpdate = false;
            }
        }
    }
    
}
 